<?php
/*
 1.Matching --> [] (Brackets)
 1.1 [0-9] any digit from 0 through 9.
 1.2. [a-z] any char from lowercase a through z.
 1.3. [A-Z] any char from uppercase A through Z.

 1.4. [A-Za-z] any char from uppercase A through lowercase z.
 1.5. [0-2b-v] 
*
*1.6. [^a-z]		negate the set from a through z, or say NOT a to z.
*
/

/*
 *  2.Quantifiers  --> + | * | ? | {n,m}
 *  2.1. p+   at least one p.
 *  2.2. p*		zero or more p's.
 *  2.3. p?		zero or one p's.
 *  
 *  2.4. p{2} 	exact contain 2 p's.
 *  2.5. p{2,3} a sequence of 2 or 3 p's.
 *  2.6. p(2, ) at least 2 p's.
 *  
 *  2.7. p$ 	string with p at the end.
 *  2.8. ^p		string with p at the beginning.
 *  
 *  2.9. [^a-zA-Z] 	string not contain a-Z.
 *  2.10. 	p.p		string containing p, followed by any char(.), in turn followsed by another p.
 *  
 *  2.11. ^.{2} 	exactly 2 any characters. ( ^ has another negation meaning when enclosed with [].
 *  2.12. <b>(.*)</b>	any string enclosed with <b> and </b>.
 *  2.13. p(hp)* 		string contain a p followed by zero or more sequence hp.
 *  
 *  
 *  3. Special Char  --> \$ | \#  (Babk slash \)
 *  3.1. 	([\$][0-9]+) 		eg. $2, $12345977
 *  
 *  
 *  4. Predefined Character Ranges 
 *  
 *  /
 
/
 * 
 * 
 * 
 * 
 */